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CNC for Green Man


#1

Greetings Fellow Orchidians, I have a real doozy of a problem here
with my newest piece, and was wondering if anyone has any good ideas
for me. It has been months that I’ve been trying to come up with an
easy solution for this. I have here a plaster casting of a carving
from Rosslyn Chapel in Scotland. It is 4.5" in diameter, and about 2"
deep. It is a famous carving of “The Green Man”, who is an ancient
"nature god" type character.

Here is a link to a photo of the carving:

http://www.alythea.com/greenman.jpg

I have been charged with making a replica of this carving as a
pendant, about 3/4" or less in diameter. Some of the methods I
thought of for doing this:

  1. Hand carve it. (Yikes! Not sure if I am even capable of this)

  2. Pantograph a copy of it using the old style 3D copying/reduction
    machine. (no luck here yet, many experts seem to think I wont be able
    to hold the detail. I actually got hold of a pantograph, but it
    appears to be busted, the motor wont run, and it’s not mine to take
    apart)

  3. Do a 3D scan, and have either a rapid prototype built, or a wax
    model milled out by CNC mill. I got one price on this, $900, which is
    too expensive for me, for this piece.

I am at an impasse, and am about to just take a straight-on digital
photo of it, reduce it to size in Photoshop and illustrator, then
print it out and trace the design onto wax. Then, just do my best
carving it. But I really want it to look as close as possible to the
original, not a poorly carved copy, so it may be sold as an accurate
reproduction.

Is there some technique I am not aware of that would make this
process easier, or does someone have the ability to scan and create a
model of this at a much cheaper price?

Thanks for any ideas!
Drew
Andrew Horn
Designer,
The Master’s Jewel
www.mastersjewel.com


#2

Hi Andrew, I do CNC work, primarily what is called 2 1/2d in the
industry, and use Rhino 3d and Mastercam. I specialize in
micro-machining and engraving with very small mills (.030" to .005"
diameter).

The $900 price seems not entirely unreasonable to me for a 3d
model…I could easily see spending 3 or 4 days to get it just right.
How many do you want? The problem with this kind of work is that the
first one costs a million dollars and the second costs $100.

2d techniques are faster but you may or may not get the result
you’re looking for. If you take a digital photo or scan the carving,
you are just capturing the front and not the sides of the object.

In any case since you are going to represent the carving on a
medallion, it won’t be possible to show the same amount of
relief…obviously a coin or medallion cannot reproduce a bust
without losing some Obviously the customer’s
expectations are extremely important…presumably they understand
this…do they expect to see just the front of the carving?

Tom


#3

use a product named “exaflex”. It’s a dental product. A two part
putty you mix and make a mold in less then 5 min. great stuff. It’s
in the dental catalogs, ask your dentist to help you get it.


#4

Drew, Look for Photogrammetry technology. This will allow you to
import several views as photographs of the subject reflecting
different angles. You will need to try and keep the same distance
from the piece on every angular shot. You will then select lines or
draw lines and points on each of the photographs that have the points
visible and these items will essentially become your datum locators
for a better sense of the word. Once you have done all of this, it
will create a 3D Model for you. Export will allow 3D DXF (.dxf), and
3D Studio (.3ds), so you may need someone to convert these files into
STL for you, which at a pinch I would help you out with. From there
just scale accordingly and machine. This company used to have a demo
available, but I am not sure if they still do. If not, I have one
somewhere that I can put up on my FTP site and you can download it
from there so that you may play with it first. I do not remember if
the demo allowed export or not, I have a feeling that it did if my
memory still serves. http://www.photomodeler.com

Best Regards.
Neil George
954-572-5829


#5

Drew- There’s no getting around the fact that if you want
3-dimensional figurative craftsmanship you have to carve it by hand.
Lost-wax process is the most efficient. I highly recommend Blue
Carvex. It’s a challenge but that’s what makes our work enjoyable.

See my website (under Recent Works-Gargoyles) for examples of what
can be achieved.

Good Luck.
Kim.
www.kimericlilot.com


#6

rio grande has a molding compound that shrinks when you make the
mold 50% called Reduc-it sounds perfect for your job Anna


#7

Hello Andrew , I carve waxes by hand and also have a 2 1/2 D scaning
and milling machine that will pruduce a 3/4" carving wax for you for
a couple of hundred pounds .(I am in England by the way). The only
drawback is that it will not have any undercuts, these would have to
be put in by hand afterwards but at least you would be able to
continue them off the rest of the carving. I could do this for you or
you could do it yourself if you feel happy about doing it. Sorry
about taking a long time to reply , major systems crash ! lost
drivers etc.If you are interested contact me off list at
@tim Tim.